Cygnus OB2-12

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Cygnus OB2-12

Cygnus OB2-12
Observation data
Epoch J2000
Constellation
(pronunciation)
Cygnus
Right ascension 20h 32m 40.9589s
Declination +41° 14' 29.286"'
Apparent magnitude (V) 11.4
Characteristics
Spectral type B5Iab
U-B color index ?
B-V color index ?
Variable type None
Astrometry
Proper motion (μ) RA: 1.91 mas/yr
Dec.: -2.47 mas/yr
Parallax (π) -0.60 ± 2.07 mas
Distance approx. -5000 ly
(approx. -2000 pc)
Absolute magnitude (MV) -10.6
Details
Mass 92 M
Luminosity 6,300,000 L
Temperature 18,500 K
Age 6.43 million years years
Other designations
VI CYG 12, JP11 5836, ALS 11417, Cl* NGC 6910, RLP 10, LS III +41 34, CSI+41-20309 2, GSC 03157-00785, 2MASS J20324096+4114291, CXOCyg J203240.94+411428.8, HBHA 4203-50, MHA 289-51, DO 38538, HIC 101364, NSV 13138, 1E 203053+4104.2, Hilt 992, RLP 41, 2E 4378, HIP 101364, ROE 960, 2E 2030.8+4104, IRAS 20308+4104, Schulte 12, EM* AS 424, IRC +40430, UBV M 51941.
Database references
SIMBAD data

Cygnus OB2-12 is a very bright blue supergiant with an absolute bolometric magnitude -12.2 (all electromagnetic radiation), which approaches the upper limit possible for star luminosities. This makes the star more than 6 million times brighter than Sun. It resides in a volume in the Milky Way from which the light towards Earth is heavily dispersed ("extinction") by interstellar dust. Where it not for intermediate dust, the star would have had a apparent visual magnitude about 1.5, as bright as Deneb (Alpha Cygni), but the actual apparent visual magnitude is 11.4, so that it requires binoculars or a lesser telescope to be seen.

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